The present disclosure relates generally to methods for growing fungal materials and objects therefrom, and in particular to a method for producing fungal materials and objects with variable shape, size, thickness, density, flexibility, and other predetermined qualities through directed and controlled tissue development and post-growth processing.
The material of a plant's body is formed from carbon and other elements filtered from the air, then bound together into sugars and other large molecules using energy from the sun. Mushrooms lack the ability to synthesize their bodies directly from sunlight and, like animals, need to consume things that were once alive in order to survive and grow. Filamentous fungi grow their bodies as an expanding and interconnected web of threadlike cells (called hyphae) directly within the food they are in the process of consuming as nutrients. The threadlike hyphae of the growing fungi exude strong enzymes and other agents into the wood or other substrate material it is living within and dissolves the molecular bonds that provide these substrates their structure. The fungus absorbs dissolved nutrients taken from the cellulose, lignin, and other substances present, which it then uses to build chitin, the resilient and strong protein that comprises its own hyphal walls. Chitin, like cellulose and keratin, is a naturally forming polymer that is found in the toughest organic tissues. In addition to being found in all fungi, chitin helps create the durable and flexible exoskeletons of insects and shellfish. These remarkable qualities are due in great part to the structure of the tissues constituent parts as well as the properties of the materials that make them up.
Filamentous fungi have the natural tendency to join together smaller pieces of branching, colonial hyphae into a larger constituent whole, assembling and weaving strands and sheets of tissues called mycelium. Mycelium can adhere to, and possibly engulf, any other materials it comes in contact with through the extension of hyphae that use neighbor sensing and searching functions as guidance in their exploration into space beyond sources of nutritional sustenance. Like cement and plaster, fungal tissue will bind, harden and set into a variety of solidified configurations through the natural biological functions of mycelial growth and self-adhesion.
Fungal tissue can quickly be amplified to an enormous volume if provided with the appropriate living conditions. These conditions include the nutrients that might be available to the organism, the possible gas gradients within the growth environment and the humidity, light, and temperatures the organism might be exposed to as it takes form. Fungi are very sensitive to their surroundings, and by altering subtle factors it is possible to prompt their tissue to express a range of variably determined physical characteristics.
Fungi are very sensitive to chemicals present in their environment, and have the ability to alter the directions and vigor of growth of expanding hyphae as demonstrated through chemotaxic avoidance or attraction. Fungi are also very sensitive to other stimuli in their environment, and have the ability to alter directions and vigor of growth of expanding hyphae in response to gravitropic, thermotropic, thigmotropic, phototropic, and hydrotropic stimuli.
A substrate colonized with fungal hyphae, if provided adequate enclosure and environmental controls, will in a matter of one to three days generate a layer of fungal hyphae growing from the top of said substrate that will expand into space as a layer in a fuzzy and undifferentiated manner. This undifferentiated layer of hyphae, if left to continue growing, will soon advance in development and differentiate into specialized tissues determined to become fruit bodies or other sporocarp-producing structures.
Fungus-based materials and composites can be propagated on readily available agricultural waste, using principles and techniques that are well established with regard to growing filamentous fungi for human consumption and industry.